Conventionally, for a cord guard protecting a cord connected with a power tool, it is known that the cord is inserted into one end of the power tool. The cord and guard are fixed in the housing of the power tool. The cord guard has a tapered tubular portion the wall thickness of which is reduced with a constant taper toward the other end (e.g. see Japanese Non-examined Utility Model Publication No. 63-46892).
Such a cord guard is mounted on the cord for the purpose of enhancing the cords durability. More specifically, the cord is prevented from being abruptly bent or kinked at the exit of the housing, since the cord guard is flexed smoothly when the cord is pulled taut while the power tool is in use. Accordingly, the cord guard itself has a certain degree of bending strength such that it will not kink by a light load approximately equal to the weight of the cord.
For example, when a worker installs a lightweight ceiling with a power tool, such as an electric screw driver at a construction site, the worker sets a screw on the tip of the driver bit of the electric screw driver, and then, screws the ceiling material with the driver bit pointed upward. This operation is repeated over and over again. In this case, the cord applies a load approximately equal to its own weight.
While, as aforementioned, the conventional cord guard has a certain degree of bending strength so that it will not flex or bend with such a light load as is approximately equal to the weight of the cord. As a result, the cord is abruptly bent or kinked at the second free end of the conventional cord guard.
Now, the problem is that the cord is frayed and ultimately disconnected before long if it is repeatedly bent or kinked abruptly at the second free end of the cord guard. For example, during installation of a lightweight ceiling with a screw driver, generally tens of thousands of repeated operations result in fraying the cord, and each time the cord is frayed, the operations must be interrupted to repair the cord, which is really troublesome. Since wages for installing a lightweight ceiling depend on how many ceiling materials the worker can install within a limited time, a cord which needs repairing after being used only tens of thousands of times is not sufficiently durable. Therefore, it is expected that the durability of the cord will be enhanced.